IDBTransaction.mode

The mode read-only property of the IDBTransaction interface returns the current mode for accessing the data in the object stores in the scope of the transaction (i.e. is the mode to be read-only, or do you want to write to the object stores?) The default value is readonly.

Syntax

Value

An IDBTransactionMode object defining the mode for isolating access to data in the current object stores:

Value

Explanation

readonly

Allows data to be read but not changed.

readwrite

Allows reading and writing of data in existing data stores to be changed.

versionchange

Allows any operation to be performed, including ones that delete and create object stores and indexes. This mode is for updating the version number of transactions that were started using IDBDatabase.setVersion(). Transactions of this mode cannot run concurrently with other transactions. Transactions in this mode are known as "upgrade transactions."

Example

In the following code snippet, we open a read/write transaction on our database and add some data to an object store. Note also the functions attached to transaction event handlers to report on the outcome of the transaction opening in the event of success or failure. At the end, we simply log the mode of the current transaction using mode. For a full working example, see our To-do Notifications app (view example live.)

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